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Edited ch06.asciidoc with Atlas code editor

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nadams 2017-05-11 06:01:09 -07:00
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@ -427,18 +427,18 @@ The validation software combines the locking and unlocking scripts and the resul
2 3 OP_ADD 5 OP_EQUAL
----
As we saw in the step-by-step example in <<simplemath_script>>, when this script is executed, the result is +OP_TRUE+, making the transaction valid. Not only is this a valid transaction output locking script, but the resulting UTXO could be spent by anyone with the arithmetic skills to know that the number 2 satisfies the script.
[[simplemath_script]]
.Bitcoin's script validation doing simple math
image::images/mbc2_0604.png["TxScriptSimpleMathExample"]
As we saw in the step-by-step example in <<simplemath_script>>, when this script is executed, the result is +OP_TRUE+, making the transaction valid. Not only is this a valid transaction output locking script, but the resulting UTXO could be spent by anyone with the arithmetic skills to know that the number 2 satisfies the script.
[TIP]
====
((("transactions", "valid and invalid")))Transactions are valid if the top result on the stack is +TRUE+ (noted as ++&#x7b;0x01&#x7d;++), any other nonzero value, or if the stack is empty after script execution. Transactions are invalid if the top value on the stack is +FALSE+ (a zero-length empty value, noted as ++&#x7b;&#x7d;++) or if script execution is halted explicitly by an operator, such as +OP_VERIFY+, +OP_RETURN+, or a conditional terminator such as +OP_ENDIF+. See <<tx_script_ops>> for details.
====
[[simplemath_script]]
.Bitcoin's script validation doing simple math
image::images/mbc2_0604.png["TxScriptSimpleMathExample"]
The following is a slightly more complex script, which calculates ++2 + 7 -- 3 + 1++. Notice that when the script contains several operators in a row, the stack allows the results of one operator to be acted upon by the next operator:
----
@ -486,7 +486,6 @@ When executed, this combined script will evaluate to TRUE if, and only if, the u
Figures pass:[<a data-type="xref" href="#P2PubKHash1" data-xrefstyle="select: labelnumber">#P2PubKHash1</a>] and pass:[<a data-type="xref" href="#P2PubKHash2" data-xrefstyle="select: labelnumber">#P2PubKHash2</a>] show (in two parts) a step-by-step execution of the combined script, which will prove this is a valid transaction.((("", startref="Tsript06")))((("", startref="Stransact06")))
[[P2PubKHash1]]
[role="smallereighty"]
.Evaluating a script for a P2PKH transaction (part 1 of 2)
image::images/mbc2_0605.png["Tx_Script_P2PubKeyHash_1"]